Spontaneous Magnetostriction Of Nd(2)Aife(14)Mn(2) Compound

Compound of Nd2AlFe14Mn2 was prepared by are melting in an argon atmosphere of high purity. The negative thermal expansion and spontaneous magnetostrictive deformations of Nd2AlFe14Mn2, compound were investigated by means of x-ray diffraction and magnetization measurements. It indicates that the Nd2AlFe14Mn2 compound has a rhombohedral Th2Zn17-type structure from 104 to 655 K.X-ray diffraction of Nd2AlFe14Mn2 compound from 263 to 364 K shows that a negative coefficient of thermal expansion exists, alpha=2.44x10(-5) K-1. The dependences of unit-cell parameters of Nd2AlFe14Mn2 compound versus temperature at the paramagnetic state were obtained according to Debye theory and Gruneisen relation. There exists a strong and anisotropic spontaneous magnetostriction in the magnetic state of Nd2AlFe14Mn2 compound. The result of magnetization measurements shows that the Curie temperature of Nd2AlFe14Mn2 compound is about 140 K lower than the mother compound Nd2AlFe16. This is probably a consequence of the magnetic moment of Mn atom being antiparallel to the magnetic moment of Fe atom in 3d-sublattice.